Challenges in implementation of Underground Coal Gasification

Project

The Presentation

Energy Scenario and UCG

UCG – A Brief

ONGC’s Experience

Learnings

Sum up

India… 16% of Global population

0.5% of world’s petroleum reserves

7.1% of coal reserves

Targeting 8-9% GDP Growth, the CAGR in primary energy demand works out to 4.5%

India faces a formidable challenge on Energy front

INDIA….

Has the 4th largest coal reserves in the world (264 Billion Tons)

Ranks 3rd in coal production (492.95 Million TPA)

Total Recoverable reserves are only about 20%

Underground Coal Gasification is the only way to harness these unrecoverable reserves

The Presentation

Energy Scenario and UCG

UCG – A Brief

ONGC’s Experience

Learnings

Sum up

What is Underground Coal Gasification?

UCG Process

Drilling of adjacent bore holes in the coal seam and its linkage

Down hole ignition of the coal seam

Injection of a pressurised oxidant such as air/oxygen and steam

Removal of product gas to surface.

Underground coal gasification (UCG) Converts coal / lignite in-situ into a gaseous product, commonly known as synthesis gas or syngas.

Sounce: http://www.ausairpower.net/APA-USAF-SynFuels.html

Carbon/coal gasification reactions

Partial Combustion C + O2 = 2CO exothermic

Combustion C + O2 = CO2 exothermic

C + CO2 = 2CO endothermic

Water-Gas C + H2O = CO + H2 endothermic

Hydrogasification C + 2H2 = CH4 exothermic

Shift CO + H2O = CO2 + H2 exothermic

Reformation CO + 3H2 = CH4 + H2O exothermic

AIR

CO2 %, 19.35

CH4 %, 2.26

CO %, 7.48

H2 %, 14.63

N2 %, 56.16

H2S %, 0.1

Cal. Value : 3.43 MJ/M3

AIR ENRICHED WITH 50% O2

CO2 %, 26.8

CH4 %, 3.4

H2S %, 0.2N2 %,

19.7

H2 %, 34.1

CO %, 15.7

Cal. Value : 6.77 MJ/M3

AIR ENRICHED WITH 65% O2

CO2 %, 27.9

CH4 %, 3.6

CO %, 16.3

H2S %, 0.2N2 %,

16.5

H2 %, 35.5

Cal. Value : 7.34 MJ/M3

AIR ENRICHED WITH 95% O2

CO2 %, 29.9

CH4 %, 3.9

H2S %, 0.2

CO %, 19

N2 %, 4.1

H2 %, 42.8

Cal. Value : 8.93 MJ/M3

Composition of typical dry UCG product gas with increase of O 2 enriched Air

SYN GAS

Power

Nitrogenous Fertilizers

Petrochemicals

Liquid Fuels

Product usage….

Underground Coal GasificationUnderground Coal Gasification

Technology plays an important role UCG process

Well configuration and well spacing

Different types of wells such as vertical, inclined or horizontal, with intersections

Wells to be completed properly with special high temp. resistant cements, tubular and well heads

Injectors & producers need to connected and gasification passage Flame treated

Compression and injection of the air & steam through the set of injector wells for maintaining gasification

Producing, cooling and processing of the produced gas

The Presentation

Energy Scenario and UCG

UCG – A Brief

ONGC’s Experience

Learnings

Sum up

UCG Pilot Flow Diagram

Detailed Exploration

Site selection

Pilot Design

MiningLease

LandAcquisition

Drilling of wells

Commissioning of Surface Facilities

Linkage of Wells,Flame Treatment

Trial Run of UCG Pilot

Environmental Clearance

Fabrication, Erection of Surface Facilities

13

1st stage : Site Selection

ONGC working with Russian scientists to test UCG technology

MoUs also signed with coal companies

Fifteen sites studied – Five sites found suitable for UCG

One site in South Gujarat, prioritized for UCG pilot study

The site is adjacent to the pit head Power Plant

DETAILS OF UCG BLOCK

2nd stage : Detailed geological and Hydro geological studies

More than 20 boreholes drilled

Detailed Geological and Geo-mechanical studies carried out

Hydrological & Hydrodynamic studies carried out

HRSS carried out

250X250-Line Interval

Lines Covered (FS 06-07)

Well for loggingDrilled Bore wells

Lines Covered (FS 07-08)

L1L2

L3L4 L5

L6L7L8

L9L10

L11L12

L13L14

L15L16

L17L18

L19L20L21

L22L23

L24L25

L26L27L28L29

L30L31

Seismic Grid

Structure Contour Map of Seam1 (based on 2D HRSS)

V 7

F

F

F

F

V-07

V-07

Based on bore well data Based on HRSS data

Lin

e-1

Lin

e-2

Lin

e-3

Lin

e-4

Lin

e-5

Lin

e-6

Lin

e-7

Lin

e-8

Lin

e-9

Line-

1L

ine-

2L

ine-

3L

ine-

4L

ine-

5L

ine-

6L

ine-

7L

ine-

8L

ine-

9

Line-32

Line-10

Line-11

Line-12

Line-13

Line-14

Line-15

Line-16

Line-17

Line-18

Line-19

Line-20

Line-21

Line-22

Line-23

Line-24

Line-25

Line-26

Line-27

Line-28

Line-29

Line-30

Line-31

Line-31Line-30Line-29Line-28Line-27Line-26Line-25Line-24Line-23Line-22Line-21Line-20Line-19Line-18Line-17Line-16

Line-15Line-14Line-13Line-12Line-11Line-10Line-32

Based on Seismic data

V-07

Structure contour map

3rd stage : Pilot Design

Pilot lay out firmed up

Detailed Engineering Design is available

The Commercial UCG Station Well Pattern…..

The Presentation

Energy Scenario and UCG

UCG – A Brief

ONGC’s Experience

Learnings

Sum up

UCG is a site specific technology

Data required for proper site selection is not usually available with the mining companies

Large amount of data like the hydro-geological data, seismic data, geo-mechanical data etc. has to be generated

All these data generation can tend to delay the time schedule of the project, if not accounted for properly

Site Selection Drilling of

Boreholes

Geophysical Logging

Hydro-geological

studies

Seismic Survey

•Geo-chemical Studies •Petro-physical Studies•Geo-mechanical Studies•Maceral Studies

Sample collection &Lab Studies

Flow Diagram for Site Selection

Compilation and Analysis of

existing data

Detail Field Investigation

Topographical data

Geological Data

Hydrological Data

• Hydro-dynamicparameters

• Chemical composition

• Precise Fault mapping• Continuity of

coal/ lignite beds

Boreholes

Geophysical Logging

Seismic Information

23

FF

FF

FF

FF

V-07V-07

V-07V-07

Use of seismic as an exploratory tool vis – a vis borehole drilling

Based on borehole data Based on HRSS data

UCG process is technology dependent

Process wells in a UCG panel involves a combination of vertical and horizontal wells which need to intersect to make a gasification passage

High degree of accuracy Drilling challenge to drill horizontal

sections of more than 100 meters through coal / lignite at shallow depth

Producers and injectors need to be interlinked and flame treated

Syngas that is produced is at a high temperature of around 2000 C and needs to be cooled down before processing

The clean up process will change with the end usage and is not similar to the one for conventional HC gas

Project is technologically dependent - ready on the shelf solutions are not available

Claimed to be available with only selected few

UCG & Economics

No authentic publication of figures in literature for carrying out cost economics

Sale of Syngas considered on energy basis (rate / BTU) will give the project a technological disadvantage

Costing of a UCG Project and economic calculations thereof are a challenge

A pilot must be considered as an R&D investment to boost the development of UCG in India

Regulations

Gazette notification Issued in July 2007 UCG can be end uses for the act

Guidelines for UCG Issued in July 2009 Provision for nomination of coal blocks to

National coal companies The applicant company should have minimum

net worth of Rs. 200 crores The applicant company should have

collaboration /tie up with the proven technology providers

The normative time limit Explored Blocks - 36 months Unexplored Blocks -24 months +36 months

Penalty for slippage in meeting time limit

Flow diagram of UCG Commercial Plant

Site Selection

Demo Plantof

End Usage

Post Pilot Monitoring

UCG Pilot

Detailed Characterization

CommercialUCG Station

Start

UCG is site specific technology It requires pilot testing before commercialisation

Linc Energy – Chinchila Pilot(1999 - 2003)Restarted Commercial operations in 2007 and reached up to Demo in 2009

A demo plant has to be consideredbefore commercialisation

Govt. coal companies given preference forNomination of Blocks

The Presentation

Energy Scenario and UCG

UCG – A Brief

ONGC’s Experience

Learnings

Sum up

The energy requirements of India are expected to grow by CAGR of 4%. Coal will continue to occupy centre-stage of India's energy scenario

UCG is the only feasible technology to harness energy from deep unmineable coal seams, in an economically and environmentally clean way

ONGC has embarked on a highly prestigious project of UCG and is poised to demonstrate the UCG technology in the near future

Summing up

Cont… The complexity of UCG makes it technologically

dependent where still ready on the shelf solutions are not available. The technology required for drilling, linkage, flame treatment and hot gas clean up is claimed to be available with only selected few

Costing of a UCG Project and economic calculations thereof are a challenge

The present statutory regulations require further refinement

Recommendations Preference for award of coal blocks should also be

given to other coal companies who can demonstrate the technology early

Provision of a pilot and a demo plant has to be made in a UCG Project, which if successful should be followed by a commercial venture. This will necessitate increasing the normative time for commercialization of UCG in the guidelines

Since UCG is a complex underground process, which is yet to be commercialised in India, it requires support of GoI in the form of relaxation in policies and a lucrative economic package. This will help in faster development of UCG Technology in India

Geological Section of Vastan (Dip)

DD:249.7

DD:342

DD:280.5

DD : 249.7 m

DD : 342.0m

DD : 280.5 m

V-1V-13V-7 NW

SE

ALLUVIUM/VAR.CLAY

LIMESTONE

FOSSILIFEROUS CLAY

CLAYSTONE

LIGNITE

FAULT

LEGEND

CH424%

C0231%

C018%

H227%

Composition of typical dry UCG product gas

(Calorific Value 13.6MJ/Nm3)(Calorific Value 13.6MJ/Nm3)

(Spanish Trial-Gasification with Oxygen)

N251%

CH41%

H222%

CO219%

H2S0%

CO7%

(Angrenskaya – Gasification with Air Injection)

(Calorific Value 3.5 MJ/Nm3)(Calorific Value 3.5 MJ/Nm3)

Product Gas Composition

Composition Wet Gas, % Wt Dry Gas, % Wt

CO2 13.83 19.37

CH4 1.38 1.94

CO 5.34 7.48

H2S 0.08 0.10

H2 10.45 14.63

N2 40.11 56.16

H2O 28.58 0

C2H4 0.23 0.2

O2 0 0

Flow sheet of gasifier, UCG pilot

Earlier Field Trials

UCG has been tested in many different experimental tests in many countries.

The Former Soviet Union executed over 50 years of research on UCG, field tests and several commercial projects, including an electric power plant in Angren, Uzbekistan that is still in operation today after 47 years.

The U.S. carried out over 30 pilots between 1975 and 1996, testing bituminous, sub-bituminous, and lignite coals.

Since 1991,China has executed at least 16 tests, and has several commercial UCG projects for chemical and fertilizer feedstocks.

In 2000, Australia began a large pilot (Chinchilla) which produced syngas for 3 years before a controlled shut-down and controlled restart.

At present, multiple commercial projects are in various stages of development in the U.S., Canada, South Africa, India, Australia, New Zealand and China to produce power, liquid fuels, and synthetic natural gas.

Development of a Generalized Simulation Model

Factors to be considered

Drying of porous media Devolatilisation or pyrolysis of coal Gasification reactions of char with oxygen, carbon dioxide,

steam and hydrogen Gas phase reactions – combustion, water-gas shift and

methanation Gas flow – turbulent and laminar Heat transfer – conduction, convection and radiation Water flow through porous media Physical and thermal degradation of solids Site layout and geophysics

Downstream Application of the Syngas:

Dimethyl Ether (DME) can be used : For Power Generation, As LPG Substitute, As

Transportation fuel, As Chemical feedstock etc. Methanol to Olefins (MTO)

Coal gasification route can be extended to manufacturing olefins

from methanol (called MTO). Coal to Liquid Petroleum (CTL) The project involves direct conversion of coal to syngas,

from which hydrogen will be separated to be further processed along with coal to produce liquid hydrocarbon (Fischer Tropsch process). This liquid hydrocarbon will be refined / distilled like in a typical refinery to produce gasoline and diesel, naphtha etc. Waxes are the byproduct of this process.

Downstream Application of the Syngas:

Ammonia / Urea N2+3H2 2NH3 2NH3 + CO2 CO(NH2)2 +H2O Methanol for Gasoline Blending

CO + 2H2 CH3OH

Dimethyl Ether (DME) MeOH Synthesis CO + H2 CH3OH

MeOH Dehydration2CH3OH CH3OCH3 + H2O

Water Gas ShiftH2O + CO H2 + CO2 Net Reaction: 3H2 + 3CO CH3OCH3 + CO2

Process efficiencies

Process EfficiencyIGCC ~45.0%

Conventional coal ~37.0 %

UCG-CO2 separation

39.8 %

Oxygen UCG 46.5 %

Air UCG 45.4 %

•Efficiency of processes for electricity production

• The gasification occurs within a bubble in an aquifer the gas pressure inside the bubble prevents the water from quenching the

reactions.

• Due to the elevated temperature of the gas, water evaporates into the bubble and it is only the flow of water through the surrounding solids that prevents the gas bubble from expanding excessively, a situation that can lead to loss of gas into the surrounding strata.

• The location and size of the bubble will depend on factors such as

the gas pressure, temperature and water inflow rates.

• Release of volatiles from the coal is likely to cause hot regions due to combustion of the volatiles, causing localized drying. Conversely, in cold regions it is likely that water will seep into the void and

reactions will be extinguished.

Concept of UCG Process

•While char combustion is possible in the void, it is unlikely that it will be sustained due to all oxygen being consumed before it can contact the char surfaces.

• Most char will be consumed by steam and carbon dioxide gasification reactions, with steam dominating due to the high moisture levels.

• As these reactions are endothermic, they require that the char must be kept hot for reaction rate to be maintained. This requires locally high gas temperatures and heat transfer through radiative or convective means,

• The driving force for a sustainable UCG process will be the combustion of volatiles and gasification product gases by the injected oxygen.

Concept of UCG Process

Shift conversion:

CO + H2O CO2 + H2 + 42.3 KJ/ Kmole The rxn is used to adjust H2/ CO ratio in the feed gas for methanation/ hydrogenation rxns. Also used in reforming rxn of CH4. and NH3 production.

Methanation/ Hydrogenation reactions:

is used to produce additional CH4 from H2 and the oxides of carbon in case of SNG production.

CO + H2 CH4 + H2O

Steam reforming:

CH4 + H2O CO + H2- 206 KJ/ Kmole

CH4 + 2 H2O CO2 + H2- 167 KJ/ mole

The CH4 is reformed under specific CO/ H2 ratio thru shift conversion of CO

Potential of UCG Syngas ~64.17 TCM

What UCG can offer for India …

303 Billion Tons (Coal+Lignite Reserves)

47 Billion Tons

(Minable Reserves)

256 Billion Tons

(Unminable Reserves)

25.7 Billion Tons

(Reserves amenable to UCG)

India’s Energy Mix (Requirement)

Total 306 kgoe Total 1125 kgoe

Source: Integrated Energy Policy, Govt. of India, Planning commission, New Delhi

2004 % Share of Commercial Primary Energy

Resources

Nuclear1.5%

Hydro 2.1%

Coal51.3%

Oil36.3%

Natural Gas8.8%

2032 % Share of Commercial Primary Energy

Resources

Natural Gas11.9%

Oil29.4%

Coal50.6%

Hydro 2.1%

Nuclear5.9%

Oil consumption to grow by CAGR 4.0%

Gas consumption to grow by CAGR 6.1%

Underground Coal GasificationUnderground coal gasification (UCG) is the in-situ conversion of coal into combustible gases (CO, H2 & CH4)

•A complex process involving•chemical reactions •heat and mass transfer•complex flow dynamics &•growing cavity dimensions.

•Advantages over conventional process are•Low dust and noise•No ash handling at power stations•No coal stocking and transportation•Larger coal resource exploitation•Converts sulphur (S) to H2S and nitrogen (N) to NH3 instead of SO2 and Nox

•Disadvantages–Surface subsidence–Aquifer water contamination

Revival of Interest in UCG

Early part of last century -there was lot of interest in UCG especially in erstwhile USSR

Subsequently, huge natural gas reserves were discovered in Russia-interest in UCG died out

Surge in demand for energy as well as prices of crude oil has renewed interest in UCG all over the world

Recently, Australia and South Africa have carried successful tests. In China and other parts of the world several projects are planned/ being carried out

49

ONGC an Indian State Enterprise…

and an integrated Oil & Gas Corporate

with interests in E&P, Refining, LNG, Power, Petrochemicals & New sources of energy

… a reliable energy solution provider for the country

In pursuit of new Energy Sources

CBM: Coal Bed MethaneUCG: Underground Coal Gasification

Synergies between Oil & Gas and UCG

Drilling

Oil and Gas Oil and Gas ExplorationExploration

andand ProductionProduction

UndergrounUnderground coal d coal

GasificationGasification

Intelligent well completions

Coiled-tubing techniquesOil & Natural gasProcessing

In-situ combustion

Pneumatic fracturing techniques

Compression & transportation of Natural gas

Exploration

Commercial UCG Station

V-7

V-1

V-13

V-8

V-14

V-2

V-3

V-4

V-5

V-6

V-15

V-16

V-17

V-18

V-9

V-10

V-11

V-12

Plan to produce Plan to produce 2 BCM Syngas from2 BCM Syngas fromtwo gasifiers per yeartwo gasifiers per year

Suggestions

Inclusion of Pilot and demo plant to be considered in the overall scheme thereby increase in time limit for commercialisation

Preference for award of coal blocks be given to companies who can demonstrate the technology early

Lucrative economic package by the GoI will help faster development of UCG Technology in India